Alkyl aldosides are important industrial products which can be used as intermediates in the synthesis of surfactants and to make polyol glycosides which are useful as initiators in the manufacture of rigid polyurethane foams. There is considerable prior art regarding various methods of making alkyl glycosides. However, to applicants' knowledge, there has not been a successful continuous method of making alkyl glycosides directly from starch.
There are some important economic advantages in a continuous process for making alkyl glycosides from starch. For example, starch is a plentiful and inexpensive raw material. It can be easily handled and can be readily slurried in a lower alcohol such as methanol.
In a continuous reaction process, there is less waste of reagents. Higher temperatures, but for much less time, can be used to drive the reaction to completion. Higher yields of purer product can be obtained because the heating is instantaneous and under pressure. There is less opportunity for the formation of color bodies, and for side reactions which form undesirable impurities. In addition, repolymerization of the alkyl glycosides obtained from the continuous alcoholysis process is minimized because the temperature of the reaction mixture drops almost instantaneously after leaving the reaction zone.